1. Field of the Invention
The present invention relates to semiconductor structures and, more particularly, to a high temperature semiconductor device and a method of manufacturing the device.
2. Description of the Related Art
Semiconductor devices are versatile and are used in many applications in many different industries. However, many applications that could more fully benefit from the use of semiconductor devices have been precluded from their use due to harsh operating environments. For example, industrial environments where high temperatures are experienced.
A demand exists in aerospace, automotive and other industries for high temperature control and power electronics, which can be mounted very, close in proximity to a heat source, such as, a combustion chamber for an internal combustion engine. By providing a high temperature integrated circuit or semiconductor device many discrete components may be replaced by a single chip. In this way, a more compact and lightweight device may be implemented with less fasteners and electrical wires. Further, integrated semiconductor devices provide more intelligent functions and programming capability. The smaller size and less maintenance required for integrated semiconductor devices aids in reducing costs as well.
Bulk silicon semiconductor devices are impractical for high temperature applications, i.e., greater than 175.degree. C. This is due to device leakage current for the bulk silicon device which doubles for every 8.degree. C. increase in temperature. In contrast silicon-on-insulator (SOI) technology devices have been demonstrated to produce functional devices up to about 400.degree. C. However, despite operational benefits of SOI technology, high temperature devices suffer from increased likelihood of electromigration failures.
Referring to FIG. 1, a conventional layout of a semiconductor device 10 is shown having arrows representing currents. The arrow size, indicated in FIG. 1, is proportional to the magnitude of the current at the various locations on device 10. Device 10 includes gate structures 12 and metal lines 14. Below metal structures are diffusion regions (not shown) common to semiconductor transistor devices. During operation currents are generated in device 10 as indicated. In a high temperature application electromigration failures occur in places where the current density is highest. Therefore, a highest probability of electromigration failure will occur in regions 16, 18 and 20 at the ends of device 10.
Therefore, a need exists for a semiconductor device that may be 5 used under high temperature conditions. A further need exists for a semiconductor device that reduces the risk of electromigration failures despite high temperature operation.